G.R.I. 1943 No1 Mk3 (GSA) -- help ID'ing markings

Just joined this forum and have already learned quite a bit just by browsing the topics. For instance, it seems Golden State Arms refurbished various portions of some post-war rifles including this one so I know it isn't original. Further, it seems the marking "GRI" signifies a British India origin of manufacture. Also, it seems "BNP" next to the Crown signifies that this weapon was in use by the British military and was tested according to the Birmingham Nitro Proof standard. However, I am still unsure as to what many of these other markings signify (I know there is a pdf floating around that explains many markings but I don't have it) so I have included images of all markings that I could find. Thanks in advance for help identifying these to better understand the history of this specific rifle. 

this has been messed about with a good bit as goosic pointed out , not unusual in the era of sante fe and a couple others but its so far from original at this point not much we can share past IDing the origins of parts as goosic did for you , 

Thanks to all three of you for the info. Apologies, I should have been more specific - the barrel of this rifle has the usual Golden State Arms etc. wording on the barrel that I've seen on others from them so I'm guessing they were the ones that refurbished this No1Mk3 rifle using lots of No4 parts as you suggest. Seems like this one is a bit more of a Frankenstein than others I've seen...